Start with proven experience, not the size of the portfolio. Ask to see three or four case studies that match your domain and your stack, and then ask which engineers actually built it. A solid partner will put you on a call with the tech lead. Evasive answers at this stage generally mean the demo work came from somewhere else.

The paperwork warrants more attention than the sales deck. Three sections matter more than the rest: assignment of intellectual property, confidentiality, and termination and handover. Every artifact should transfer to you once invoices are settled, along with designs, scripts and web development company germany infrastructure configuration. Watch for any clause that leaves so-called reusable libraries with the vendor, since this is frequently exactly the piece that locks you in.

Ask where their numbers come from. A serious estimate arrives with a written set of assumptions, ai development services a breakdown by feature or module and a best case and a worst case. A fixed price works only when the specification is complete; otherwise the provider pads the number and you fund the buffer regardless. Hourly billing moves the risk back to the client, so it needs visible weekly reporting and a spending cap.

How the work is run matters more than the number of hire react query developers. Find out how change requests are handled, who signs off on a feature and what the QA setup looks like. A well-run team will be able to walk you through a working build every one or two weeks. Written acceptance criteria are your only real protection against the it-was-never-in-scope conversation.

Last, consider the handover at the start rather than at the end. Insist that the repository lives under your account from the beginning, and that documentation is written as you go rather than left to the end. A provider confident in its own work accepts it without argument; resistance at this point tells you most of what you need to know.